1. Field of the Invention
The present invention relates generally to motion sensors and to systems incorporating such sensors, and is particularly concerned with a PIR motion sensor system.
2. Related Art
This application is related to the following U.S. patents and patent application, which are incorporated herein by reference in their entirety: U.S. Pat. Nos. 7,183,912; 7,399,970; 7,399,969; 11/134,780. These related patents and application disclose simple PIR motion sensors with low false alarm rates and minimal processing requirements that are capable of discriminating smaller moving targets, e.g., animals, from larger targets such as humans, so that an alarm is activated only in the presence of unauthorized humans, not pets.
Particularly with respect to ceiling-mounted sensors, owing to the use of positive and negative detector elements, it is possible for signals from objects to be monitored to cancel along some lines of bearing. In other words, ceiling-mounted detectors inherently have longer detection ranges along some lines of bearing and shorter detection ranges along other lines of bearing. As understood herein, it is desirable to provide a single ceiling-mounted detector that has relatively uniform detection capability along all lines of bearing.